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Record W4396601230 · doi:10.24124/2024/59486

Unphysical behaviour of the Hinde potential energy surface: Implications for the calculation of dissociation rate coefficients of H2 + H2

2024· dissertation· en· W4396601230 on OpenAlexaff
Abid Afzal

Bibliographic record

Venuenot available
Typedissertation
Languageen
FieldPhysics and Astronomy
TopicAdvanced Chemical Physics Studies
Canadian institutionsUniversity of Northern British Columbia
Fundersnot available
KeywordsDissociation (chemistry)Potential energy surfaceChemistryDissociation rateQuadrupoleHydrogenPotential energyChemical physicsThermodynamicsAtomic physicsPhysicsPhysical chemistryMoleculeOrganic chemistry

Abstract

fetched live from OpenAlex

Molecular hydrogen is the dominant molecular species present in the interstellar medium and has an important role in the cooling of shocks that are associated with star formation. The two mechanisms of cooling are collisional excitation followed by quadrupole emission and collisional dissociation. Modelling the role of dissociation in this cooling needs detailed information on the state specific dissociation rate coefficients. The initial goal of this research was to compare the trajectory outcomes on the Hinde potential energy surface (PES) with those on the BMKP2 PES to assess whether it is required to do extensive and more expensive calculations to determine state specific rate coefficients for dissociation of H2 + H2 to supersede those previously determined with the BMKP2 surface. A phenomenon of double dissociation was unexpectedly identified within the Hinde PES, despite the absence of sufficient energy for such an occurrence. These results prompted a comprehensive analysis of the Hinde PES, which in turn involved an exploration of the regions that exhibit unphysical behavior. This detailed examination unveiled problematic aspects of the potential energy surface. As a result of this, it has been determined that the Hinde PES is unsuitable for calculating dissociation rate coefficients for H2 + H2.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.003
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: Simulation or modeling
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.003
Threshold uncertainty score0.010

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0010.003
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0000.000
Science and technology studies0.0010.001
Scholarly communication0.0010.001
Open science0.0010.001
Research integrity0.0010.001
Insufficient payload (model declined to judge)0.0030.001

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.008
GPT teacher head0.285
Teacher spread0.277 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designSimulation or modeling
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations0
Published2024
Admission routes1
Has abstractyes

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